Expansion joint seal

ABSTRACT

An expansion joint seal for use in roadways, bridges, buildings and the like comprises a pair of elongated, parallel, spacedapart frame members, each of which has an inwardly facing, generally C-shaped cavity, and an elongated resilient gasket having a web portion spanning the space between the frame members and a retaining bead portion extending along each edge of the web portion and received within the cavity of a respective frame member. Each retaining bead portion has an inwardly facing concavity that divides the bead portion into two parts that are bendable toward each other to reduce the maximum dimension of the bead portion and permit it to be inserted through the opening of the cavity in the respective frame member. The web portion is joined to each bead portion exclusively at one of the two parts defined by the concavity.

United States Patent 1 Reifsnyder i 1 EXPANSION JOINT SEAL [75] Inventor: Howard B. Reifsnyder,

Williamsport, Pa.

[73] Assignee: Construction Specialties Inc.,

Cranford, NJ.

221 Filed: Sept. 20, 1974 21 App] No.: 507,664

[ June 10, 1975 Primary Examiner-Nile C. Byers, Jr. Attorney, Agent, or Firm-Brumbaugh, Graves, Donohue & Raymond [57] ABSTRACT An expansion joint seal for use in roadways, bridges, buildings and the like comprises a pair of elongated, parallel, spaced-apart frame members, each of which has an inwardly facing, generally C-shaped cavity, and an elongated resilient gasket having a web portion spanning the space between the frame members and a retaining bead portion extending along each edge of the web portion and received within the cavity of a respective frame member. Each retaining bead portion has an inwardly facing concavity that divides the head portion into two parts that are bendable toward each other to reduce the maximum dimension of the bead portion and permit it to be inserted through the opening of the cavity in the respective frame member. The web portion is joined to each head portion exclusively at one of the two parts defined by the concavity.

EXPANSION JOINT SEAL BACKGROUND OF THE INVENTION This invention relates to expansion joint seals of the type used for sealing an expansion joint space against intrusion of dirt and water. That type of expansion joint seal conventionally comprises metal frame members installed on either side of the expansion space on the structures defining that space and a resilient gasket having a web portion that bridges the space and retaining beads along each edge of the web portion that are received in cavities within the respective frame memhers to keep the gasket secured to the respective frame members.

One problem encountered with many available ex pansion joint seals is that the retaining bead becomes dislodged from one of the frames over part or all of the length of the joint with the result that the seal no longer remains watertight, and. thus, ceases to perform the function for which it was provided.

There have been various proposals for design of the retaining beads and other approaches to the design of expansion joint seals that have had the objective of minimizing the possibility of failure of the joint by dislodging of the gasket, but many of the suggested designs have not been fully successful in solving the problem. The origin of the problem is that it is, of course, necessary that the bead originally be installed in the retaining cavity of the frame member, which means that some provision must be made for reducing the size of the head to permit it to be inserted into the cavity. The most common technique for permitting the reduction in the size ofthe bead is to make it hollow, thereby permitting the bead to be compressed for reception into the retaining cavity of the frame member. Unfortunately, the hollow cavity operates in reverse, in that it can also allow the bead to be compressed in size so that it can be pulled out of the cavity under various conditions, such as after water intrusion and freezing.

SUMMARY OF THE INVENTION There is provided, in accordance with the invention, an improved expansion joint seal of the type described above that embodies an improved retaining bead. More particularly, according to the invention an expansion joint seal comprises a pair of elongated frame members installed on either side of the expansion space. Each of the frame members has an inwardly facing cavity open ing into the space. the dimension at the opening of the cavity being substantially less than the maximum dimension taken generally parallel to the opening within the cavity. A resilient gasket seals the space between the frame members, the gasket having a web portion spanning the space between the frame members and a retaining bead portion received within the cavity of the respective frame members. The outward surface of each retaining bead portion matches and is in engagement with the wall of the cavity in the frame member and has an inwardly facing concavity on its inward surface subdividing it into two parts along a bending zone such that the two parts can be bent inwardly relatively toward each other to reduce the dimension of the retaining bead and to allow it to be inserted through the opening into the cavity. The minimum dimension of the retaining head portion is preferably at a medial plane such that the two sections of the bead portion are of generally equal size in cross-section, and the crosssectional area of the concavity is generally equal to the cross-sectional area of a segment of the bead that occupies the concavity when the bead is bent for insertion in the frame member cavity.

An important aspect of the expansion joint seal, according to the present invention, is the absence of a closed structure surrounding a hollow portion of the bead. In a hollow bead there is a structural connection directly between the web portion of the gasket and those portions of the bead that are captured in the cavity so that a force acting on the web portion tending to extract the bead from the cavity is transmitted to both captured parts of the bead. With a seal according to the present invention, each bead portion of the gasket is connected to the web portion at only one of the parts on either side of the concavity so that a force acting on the web portion tending to pull the bead out of the cavity in the frame member is not transmitted to the other part of the bead and does not have the tendency to extract that part of the head as is the situation in the case of a hollow bead. Generally, the predominant effect of a force tending to pull the bead out ofthe cavity in the seal disclosed herein is merely to elongate the web portion rather than to act on both captured sections of the bead and tend to distend the bead and pull it out of the cavity in the frame member.

DESCRIPTION OF THE DRAWINGS For a better understanding of the invention, reference may be made to the following description of an exemplary embodiment, taken in conjunction with the Figures of the accompany drawing, in which:

FIG. 1 is a cross-sectional view of the embodiment; and

FIG. 2 is a cross-sectional view of one of the frame members and the bead portion of the gasket showing the head portion bent in the process installing the gasket in the frame member.

DESCRIPTION OF EXEMPLARY EMBODIMENT The reference numerals l0 and 12 in FIG. I designate structures, such as roadway pavement, a bridge pavement, floors or roofs of buildings or the like on either side of a space I4 at an expansion joint in the structure. The embodiment of the expansion joint seal illustrated in the drawing and described herein comprises a pair of elongated frame members 16, one of which is installed at the opening in each of the structures I0 and 12. In the embodiment shown in the drawing, the structures 10 and I2 are concrete and the frame members 16 are installed at the expansion joint by longitudinally spaced-apart anchors I8, joined to the frame members and embedded in the concrete. The frame members are preferably made of metal by extrusion, aluminum, stainless steel or other weather durable materials being preferred.

Each frame member includes a generally C-shaped cavity 20 that faces inwardly toward the space 14, the cavity 20 opening toward the space at an opening defined between opposed projecting portions 22 and 24 spaced from each other at a distance substantially less than the dimension within the cavity taken generally parallel to the opening, thereby to define undercut retaining portions 26 and 28 within the cavity 20.

The expansion joint seal shown in the drawing further comprises an elongated, resilient gasket 30 having a web portion 32 of generally uniform thickness that spans the space 14 and a retaining bead portion 34 extending along each edge of the web portion and received within a cavity of a respective frame member 16. The gasket is formed, such as by extrusion or molding. from a durable, moderately resilient material such as plastic or rubber, neoprene having a durometer hardness of from about 60 to about 70 being preferred.

The width of the web portion 30, measured along the cross-sectional axis, is preferably greater than the maximum dimension of the expansion space 14 so that the web portion 30 is never brought into full expansion and placed under tensile load. Thus, as installed in the expansion joint, the web assumes a trough-shape, such as the generally U or V-shape shown in the drawing, for all degrees of spacing at the expansion joint.

The outward surface of each retaining bead portion 34 of the gasket 30 generally matches and is in engagement with the wall of the cavity in the frame member. Preferably, the size of the bead is slightly greater than the size of the cavity, so that, as installed, the bead is somewhat compressed. It is also desirable, though not essential, to provide an appropriate adhesive at the interface between the bead of the gasket and the cavity of the frame member to enhance the waterproofness of the seal. The inward face of each retaining bead portion 34 of the gasket 30 is formed with a concavity 36 that divides the bead portion generally medially into upper and lower parts 38 and 40 and defines an opening zone along which such upper and lower parts are bendable relatively toward each other for substantial reduction in the maximum dimension of the bead portion to permit it to be inserted through the opening of the frame member cavity (see FIG. 2 of the drawing).

The junctures between the respective retaining bead portions 34 and the web portion 32 of the gasket are at the inward portions of the upper parts 38 of the bead portions. there being no direct structural connection between the lower parts 40 of the bead portions and the web portion 32 of the gasket. Thus, the bead portion is readily bent inwardly, as illustrated in FIG. 2, to allow the lower part 40 to be bent upwardly so that a segment ofit moves into the concavity 36 and so that the dimension between generally the upper and lower ends of the bead portion is substantially reduced to allow the bead to be inserted into the cavity in the frame member. Thus the cross-sectional area of the concavity is made to be substantially equal to that segment of the lower part of the bead portion that is received in the concavity when the lower part is bent during installation of the gasket in a respective frame member.

Referring to FIG. 2 of the drawing, the gasket is installed in the expansion joint by first inserting the upper part 38 of one bead portion 34 into the upper part of the cavity of a respective frame member 16 along a short length of the frame member. The lower part 40 of the bead, at a point when the upper part 38 is nearly fully inserted in the cavity, is partially bent upwardly into the concavity 36 (see FIG. 2), but remains outside the lower portion of the cavity. Meanwhile, the web portion can be bent up so that it leaves room to use a rolling tool having a relatively thin wheel to push the bead fully into place in the cavity, the wheel intruding into a small part of the concavity and applying a force generally outwardly so that the lower part 40 of the bead is pulled past the lower projection 24 of the frame member cavity and fully seats within the concavity. Thus the bead portion is relatively easily rolled into final position working from one end of the frame member to the other. The bead portion at the other side of the joint is, of course, installed in the same way.

Once the bead portion is installed (see FIG. I), it requires a very substantial force to dislodge it from the frame member cavity. The absence of any direct structural connection between the lower part 40 and the web portion 32 avoids the possibility of bending or distension of the bead under a load acting on the web tending to pull the bead out of the cavity. In contrast, a hollow bead having captured portions directly connected to a web or webs, as in the prior art, will tend to distend upon the application of tension to the web or webs with the result that the captured portions tend to be pulled away from seated position within a cavity, a situation that can, in the extreme, pull the bead out of the frame member cavity, and at least, affect the waterproofness of the sea].

I claim:

1. An expansion joint seal comprising a pair of spaced-apart, elongated frame members positioned substantially parallel to each other, each frame member having in cross-section a generally C-shaped cavity facing inwardly toward the space between the frame members, each such cavity opening toward the space between the frame members at an opening defined between opposed projecting portions of the frame members spaced from each other a distance substantially less than the maximum dimension within the cavity taken generally parallel to the opening. and an elongated resilient gasket sealing the space between the frame members and including a web portion spanning the space and a retaining bead portion extending along each edge of the web portion and received within the cavity of a respective frame member, each retaining bead portion having an outward surface substantially matching and in engagement with the cavity of the respective frame member and having a concavity on its inward surface facing generally inwardly, the concavity of each retaining bead portion of the gasket dividing the retaining bead portion generally centrally into upper and lower parts and defining a bending zone along which such upper and lower parts are bendable relatively toward each other for substantial reduction of the size of the bead portion such that the bead portion is receivable through the opening of a respective frame member into the cavity thereof, and each retaining bead portion joining the web portion of the gasket exclusively at one of said parts defined by the concavity.

2. An expansion joint seal according to claim 1 wherein the respective retaining bead portions of the gasket join the web portion at the upper part of the bead portion.

3. An expansion joint seal according to claim 1 wherein the minimum thickness in cross-section of each retaining bead portion of the gasket lies generally at a medial plane of the bead portion.

4. An expansion joint seal according to claim 1 wherein the area in cross-section of the concavity of each retaining bead portion of the gasket is not substantially less than the area in cross-section of a segment of the part of the bead portion that occupies the concavity when the bead portion is bent to reduce the maximum dimension thereof for reception in the cavity of a respective frame member. 

1. An expansion joint seal comprising a pair of spaced-apart, elongated frame members positioned substantially parallel to each other, each frame member having in cross-section a generally Cshaped cavity facing inwardly toward the space between the frame members, each such cavity opening toward the space between the frame members at an opening defined between opposed projecting portions of the frame members spaced from each other a distance substantially less than the maximum dimension within the cavity taken generally parallel to the opening, and an elongated resilient gasket sealing the space between the frame members and including a web portion spanning the space and a retaining bead portion extending along each edge of the web portion and received within the cavity of a respective frame member, each retaining bead portion having an outward surface substantially matching and in engagement with the cavity of the respective frame member and having a concavity on its inward surface facing generally inwardly, the concavity of each retaining bead portion of the gasket dividing the retaining bead portion generally centrally into upper and lower parts and defining a bending zone along which such upper and lower parts are bendable relatively toward each other for substantial reduction of the size of the bead portion such that the bead portion is receivable through the opening of a respective frame member into the cavity thereof, and each retaining bead portion joining the web portion of the gasket exclusively at one of said parts defined by the concavity.
 2. An expansion joint seal according to claim 1 wherein the respective retaining bead portions of the gasket join the web portion at the upper part of the bead portion.
 3. An expansion joint seal according to claim 1 wherein the minimum thickness in cross-section of each retaining bead portion of the gasket lies generally at a medial plane of the bead portion.
 4. An expansion joint seal according to claim 1 wherein the area in cross-section of the concavity of each retaining bead portion of the gasket is not substantially less than the area in cross-section of a segment of the part of the bead portion that occupies the concavity when the bead portion is bent to reduce the maximum dimension thereof for reception in the cavity of a respective frame member. 